1. Technical Field
The present invention relates to technology for preventing degradation of display quality due to so-called horizontal crosstalk.
2. Related Art
Recently, projectors that form reduced images using electro-optical panels such as liquid crystals and project the reduced images on an enlarged scale using optical systems have been used. The projectors do not have a function of generating an image and are supplied with image data (or an image signal) from higher-level devices such as PCs or television tuners. The image data is used for designating gray scale levels brightness) of pixels for each pixel. Since the image data is supplied in the form of vertical and horizontal scanning of pixels arranged in the shape of a matrix, it is appropriate to drive a display panel used in the protectors by using a method corresponding to such scanning.
Generally, display panels used in the projectors are driven by using a dot sequential method in which scanning lines are sequentially selected in a predetermined order, data lines are sequentially selected in a period (one horizontal scanning period) when one scanning line is selected, and data signals generated from converting image data appropriately for driving the liquid crystal are supplied to the selected data line.
In addition, recently, a phase development method has been proposed in which the data lines are grouped into blocks of two or more data lines, the blocks are sequentially selected each horizontal scanning period, and data signals are supplied to the data lines belonging to the selected block, for the display of a high-definition image such as a high-vision image.
However, when the above-described display panel is driven by using the dot sequential method or the phase development method there is a problem that degradation of display quality due to what is referred to as “horizontal crosstalk” occurs. The horizontal crosstalk herein is a phenomenon that, for example, in a case where a black (the lowest luminance or the vicinity thereof) rectangular area is displayed as a window over a gray (medium gray scale level) background in the normally-white mode, a gray area adjacent to the black area in a horizontal scanning direction is displayed with brightness different from that of other gray parts.
The horizontal crosstalk can be suppressed to some degree by signal processing for the image data designating gray scale levels of pixels so as to correct voltage levels of the data signals applied to pixel electrodes (for example, see JP-A-2002-116735).
However, when a configuration is used in which the voltage levels of the data signals are corrected, the generation of the horizontal crosstalk can be suppressed, but an additional circuit for signal processing in a correction process is required, whereby the structure of the device becomes complicated.